[deliverable/linux.git] / net / ipv6 / netfilter / ip6t_mh.c

/*
 * Copyright (C)2006 USAGI/WIDE Project
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Author:
 *	Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
 *
 * Based on net/netfilter/xt_tcpudp.c
 *
 */
#include <linux/types.h>
#include <linux/module.h>
#include <net/ip.h>
#include <linux/ipv6.h>
#include <net/ipv6.h>
#include <net/mip6.h>

#include <linux/netfilter/x_tables.h>
#include <linux/netfilter_ipv6/ip6t_mh.h>

MODULE_DESCRIPTION("ip6t_tables match for MH");
MODULE_LICENSE("GPL");

#ifdef DEBUG_IP_FIREWALL_USER
#define duprintf(format, args...) printk(format , ## args)
#else
#define duprintf(format, args...)
#endif

/* Returns 1 if the type is matched by the range, 0 otherwise */
static inline int
type_match(u_int8_t min, u_int8_t max, u_int8_t type, int invert)
{
	int ret;

	ret = (type >= min && type <= max) ^ invert;
	return ret;
}

static int
match(const struct sk_buff *skb,
	 const struct net_device *in,
	 const struct net_device *out,
	 const struct xt_match *match,
	 const void *matchinfo,
	 int offset,
	 unsigned int protoff,
	 int *hotdrop)
{
	struct ip6_mh _mh, *mh;
	const struct ip6t_mh *mhinfo = matchinfo;

	/* Must not be a fragment. */
	if (offset)
		return 0;

	mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
	if (mh == NULL) {
		/* We've been asked to examine this packet, and we
		   can't.  Hence, no choice but to drop. */
		duprintf("Dropping evil MH tinygram.\n");
		*hotdrop = 1;
		return 0;
	}

	if (mh->ip6mh_proto != IPPROTO_NONE) {
		duprintf("Dropping invalid MH Payload Proto: %u\n",
			 mh->ip6mh_proto);
		*hotdrop = 1;
		return 0;
	}

	return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
			  !!(mhinfo->invflags & IP6T_MH_INV_TYPE));
}

/* Called when user tries to insert an entry of this type. */
static int
mh_checkentry(const char *tablename,
	      const void *entry,
	      const struct xt_match *match,
	      void *matchinfo,
	      unsigned int hook_mask)
{
	const struct ip6t_mh *mhinfo = matchinfo;

	/* Must specify no unknown invflags */
	return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
}

static struct xt_match mh_match = {
	.name		= "mh",
	.family		= AF_INET6,
	.checkentry	= mh_checkentry,
	.match		= match,
	.matchsize	= sizeof(struct ip6t_mh),
	.proto		= IPPROTO_MH,
	.me		= THIS_MODULE,
};

static int __init ip6t_mh_init(void)
{
	return xt_register_match(&mh_match);
}

static void __exit ip6t_mh_fini(void)
{
	xt_unregister_match(&mh_match);
}

module_init(ip6t_mh_init);
module_exit(ip6t_mh_fini);
Commit	Line	Data
a0ca215a MN	1	/*
	2	* Copyright (C)2006 USAGI/WIDE Project
	3	*
	4	* This program is free software; you can redistribute it and/or modify
	5	* it under the terms of the GNU General Public License version 2 as
	6	* published by the Free Software Foundation.
	7	*
	8	* Author:
	9	* Masahide NAKAMURA @USAGI <masahide.nakamura.cz@hitachi.com>
	10	*
	11	* Based on net/netfilter/xt_tcpudp.c
	12	*
	13	*/
	14	#include <linux/types.h>
	15	#include <linux/module.h>
	16	#include <net/ip.h>
	17	#include <linux/ipv6.h>
	18	#include <net/ipv6.h>
	19	#include <net/mip6.h>
	20
	21	#include <linux/netfilter/x_tables.h>
	22	#include <linux/netfilter_ipv6/ip6t_mh.h>
	23
	24	MODULE_DESCRIPTION("ip6t_tables match for MH");
	25	MODULE_LICENSE("GPL");
	26
	27	#ifdef DEBUG_IP_FIREWALL_USER
	28	#define duprintf(format, args...) printk(format , ## args)
	29	#else
	30	#define duprintf(format, args...)
	31	#endif
	32
	33	/* Returns 1 if the type is matched by the range, 0 otherwise */
	34	static inline int
	35	type_match(u_int8_t min, u_int8_t max, u_int8_t type, int invert)
	36	{
	37	int ret;
	38
	39	ret = (type >= min && type <= max) ^ invert;
	40	return ret;
	41	}
	42
	43	static int
	44	match(const struct sk_buff *skb,
	45	const struct net_device *in,
	46	const struct net_device *out,
	47	const struct xt_match *match,
	48	const void *matchinfo,
	49	int offset,
	50	unsigned int protoff,
	51	int *hotdrop)
	52	{
	53	struct ip6_mh _mh, *mh;
	54	const struct ip6t_mh *mhinfo = matchinfo;
	55
	56	/* Must not be a fragment. */
	57	if (offset)
	58	return 0;
	59
	60	mh = skb_header_pointer(skb, protoff, sizeof(_mh), &_mh);
	61	if (mh == NULL) {
	62	/* We've been asked to examine this packet, and we
	63	can't. Hence, no choice but to drop. */
	64	duprintf("Dropping evil MH tinygram.\n");
65	*hotdrop = 1;
66	return 0;
67	}
68
138939e0 MN	69	if (mh->ip6mh_proto != IPPROTO_NONE) {
	70	duprintf("Dropping invalid MH Payload Proto: %u\n",
	71	mh->ip6mh_proto);
	72	*hotdrop = 1;
	73	return 0;
	74	}
	75
a0ca215a MN	76	return type_match(mhinfo->types[0], mhinfo->types[1], mh->ip6mh_type,
	77	!!(mhinfo->invflags & IP6T_MH_INV_TYPE));
	78	}
	79
	80	/* Called when user tries to insert an entry of this type. */
	81	static int
	82	mh_checkentry(const char *tablename,
	83	const void *entry,
	84	const struct xt_match *match,
	85	void *matchinfo,
	86	unsigned int hook_mask)
	87	{
	88	const struct ip6t_mh *mhinfo = matchinfo;
	89
	90	/* Must specify no unknown invflags */
	91	return !(mhinfo->invflags & ~IP6T_MH_INV_MASK);
	92	}
	93
	94	static struct xt_match mh_match = {
	95	.name = "mh",
	96	.family = AF_INET6,
	97	.checkentry = mh_checkentry,
	98	.match = match,
	99	.matchsize = sizeof(struct ip6t_mh),
	100	.proto = IPPROTO_MH,
	101	.me = THIS_MODULE,
	102	};
	103
	104	static int __init ip6t_mh_init(void)
	105	{
	106	return xt_register_match(&mh_match);
	107	}
	108
	109	static void __exit ip6t_mh_fini(void)
	110	{
	111	xt_unregister_match(&mh_match);
	112	}
	113
	114	module_init(ip6t_mh_init);
	115	module_exit(ip6t_mh_fini);